1. Field of the Invention
The present invention relates to devices and methods for applying electric fields to treat atherosclerotic disease. The present invention also relates to devices and methods adapted for prevention of ischemic vascular events.
2. Description of the Related Art
Implantable medical devices such as stents, vascular grafts, cardiac rhythm management devices, catheters, vena cava filters, and the like, are well known. Over the years, numerous improvements to these devices have occurred. There are still, however, difficulties. For example, in-stent restenosis is a complication where there is a reclosure of a previously stenosed coronary artery. Atherosclerosis, a common disease of the arteries, occurs where fatty material accumulates on the smooth muscle of a vessel wall, resulting in the eventual impediment of blood flow. Cardiac rhythm management devices such as pacemakers and implantable cardioverter defibrillators at times require the removal and replacement of an implanted endocardial lead. This need may arise for a variety of reasons, such as growth (in the case of children), lead failures, infections, and the like. The ease of lead removal and associated risk varies with the time that the implanted endocardial lead has been in place. A t lead that has been in place for three months or less is usually easily removed. However, a lead that has been in place for a year or longer presents removal difficulties due to fibrosis and encapsulation. These difficulties are in turn associated with mortality and significant morbidity. Pacing lead removal using simple traction is straightforward and with few complications. Unfortunately, fibrous adhesions to the Lead body complicate lead extraction and require more complex extraction techniques such as invasive surgical techniques and the use of assistive tools. As contemporary leads in use today are low profile and primarily coaxial bipolar, they do not stand up to simple traction where there is significant fibrosis present and the Lead is chronically implanted as a result. Polymethane insulated pacing leads see less fibrosis than the earlier silastic leads, but chronically implanted leads are still common. What is needed is a device that prevents fibrosis in medical devices such as cardiac pacing device leads. It is therefore an object of the present invention to provide an internal medical device that prevents or reduces fibrosis. It is another object of the present invention to provide an internal medical device that prevents or reduces fibrosis without the need for an external power source. It is another object of the present invention to provide an internal medical device that reduces atherosclerotic disease and ischemic vascular events. It is yet another object of the present invention to provide a stent for transluminal implantation that reduces the occurrence of in-stent restenosis. It is another object of the present invention to provide a vascular graft with improved healing characteristics.